The factory sight pusher is O.K. IF you are only planning on removing/replacing stock, factory plastic sights.
For any other application, a sturdier, heavier duty tool is a much better bet.
I have installed Meprolight night sights on a couple of Glocks using the factory tool.....
I've also dated a few ugly girls & drank some cheap beer in my life.
NONE of these are things I would prefer to do again.
For any serious work, I'd suggest the Meprolight sight press. It's expensive, but it will work on any known pistol slide except a Desert Eagle.
And I have changed sights on a D.E. but it takes time, a sturdy bench vise with padded jaws, a couple of brass drift punches (you WILL ruin a couple in the process) and a 2# hammer isn't overkill for this job !

I suggest saving till you can afford the Mepro tool. They also have a Kimber-specific pushing block for the Kimber shape dovetails....this also works on the new FN pistols & a lot of others. From Brownell's, the total outlay will be a bit over $400, but well worth it.
Doing a sight job with zero aggravation make a day go well !

I've used several tools in the past, some borrowed, some homemade, some factory. The tool from Meprolight beats them all.

I also suggest not getting the Glock tool because it's flimsy compared to a few others you could get. I have the MGW tool for Glock sights with slanted sides. It's just about strong enough to pull semi trucks out of the ditch. And it was actually a few bucks cheaper then the Glock tool at the time (a couple years ago). The Glock tool is for plastic sights only IMO.